Effect of acclimatization in a floating system on photosynthetic ability of pear plants (Pyrus communis L. OHF 333)

In vitro cultivated plants are maintained in a nutrient medium supplemented with carbohydrates.
This results in heterotrophic or mixotrophic growth.
During acclimatization to ex vitro conditions, plants are forced to switch to autotrophic carbon assimilation.
For this reason, acclimatization is a key stage in micropropagation.
The aim of the present research was to study the photosynthetic ability of pear plants acclimatized in a floating system.
In vitro propagated and rooted plantlets from pear rootstock OHF 333 (Pyrus communis L.) were acclimatized in a floating system with different nutrient solutions – Knopp (1865), Hellriegel (1898) or Pryanishnikov (1976). Plants were grown in a greenhouse in daylight under high humidity for one week and then the humidity was gradually decreased.
Net photosynthetic rate and chlorophyll a fluorescence (JIP test) were measured 45 days after transplanting the plants to ex vitro conditions.
The net photosynthetic rate in plants acclimatized in the floating system was higher than that of the control, with the highest value (13,5 µmol m^-2 s^-1) being in Hellriegel nutrient solution.
The photochemical activity of photosystem II estimated by the ratio Fv/Fm was within the normal range for healthy, unstressed leaves (0.75-0.85) and was less affected by the treatments.

IV International Symposium on Horticulture in Europe – SHE2021

N. Dimitrova, V. Nikolova, L. Nacheva

acclimatization, photosynthesis, transpiration rate, chlorophyll fluorescence, pear, floating system

https://doi.org/10.17660/ActaHortic.2021.1327.101